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rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load 

The rcu_request_urgent_qs_task() function does a cross-CPU store
to ->rcu_urgent_qs, so this commit therefore marks the load in
__rcu_irq_enter_check_tick() with READ_ONCE().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
This commit is contained in:
Paul E. McKenney 2023-06-26 18:37:05 -07:00
parent ed2b9e1b6d
commit 343640cb5b
1 changed files with 1 additions and 1 deletions
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2
kernel/rcu/tree.c
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@ -632,7 +632,7 @@ void __rcu_irq_enter_check_tick(void)
// prevents self-deadlock. So we can safely recheck under the lock.
// Note that the nohz_full state currently cannot change.
raw_spin_lock_rcu_node(rdp->mynode);
if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {
if (READ_ONCE(rdp->rcu_urgent_qs) && !rdp->rcu_forced_tick) {
// A nohz_full CPU is in the kernel and RCU needs a
// quiescent state. Turn on the tick!
WRITE_ONCE(rdp->rcu_forced_tick, true);